How would you add strength to this piece without a domino?

[Bryan Knitter]

I build and sell large decorative walnut crosses. I build them with miter joints in the center because, IMO, it looks awesome, pic below. Every one I've built so far, I've just used glue to hold everything together. I haven't ever had one break (knock on wood), BUT, I want to look into strengthening the joint somehow anyway, since it's all end grain to end grain. And maybe a bonus is that it makes aligning everything easier too?

I tried using this 1/4" dowel jig from rockler: http://www.rockler.com/doweling-jig-kits But no matter what I did, the pieces wouldn't properly align, so that's getting returned.

Whatever I use, I don't want it to be visible. I don't have and am not going to buy a domino. I looked at Rockler's beadlock system and I'm not a fan.

Something that came to mind is like a square spline in the center of the joint. I don't know if it'll make sense, but I'll try to explain. If I build a jig, sort of like a tenoning jig to cut a groove across the center of the end-grain of the pointed parts of each piece, then glue in a square piece of like 1/4" thick stock. Does that make any sense?

Would biscuits help? Should I stick with dowels? If dowels, where can I find a jig that isn't junk and is budget friendly?

OR

Just keep doing what I'm doing. The piece is designed to hang on a wall, so there's essentially 0 stress on the joint.


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Sorry for the brain dump. Hopefully some of that makes sense!

Thanks!

[Scott Buehler]

I like the idea of the spline. A jig should be fairly easy to make for that.

[Jamie Buxton]

A square spline is a very good idea. I'd use baltic birch 1/4" plywood.

[Matthew Hills]

I also like the idea of a hidden spline.

I'd cut a slot in the mitered ends and fit a piece in there.
It looks like you've already figured out how to get the mitered joint to come together, so you really only want this to be in there to reinforce the glue joint with something other than endgrain gluing. You can use a slot cutter on a router or a spline-cutting jig on a table saw.

Matt

[Rhys Hurcombe]

Youtube "Through Tenon with Sword Tip Miter". It will be your strongest option probably. The same idea can be translated into something that would work for your application. Only thing is, it would take a whole lot longer. I wouldn't be selling these personally without some sort of joinery aside from the straight up end grain glue up miters.

[Joe Jensen]

Yes, a square spline out of baltic birch plywood would be very strong. How long are the pieces? If less than 4 or 5 feet you could make a jig that holds the parts vertical and cut them easily on the table saw.

[Andrew Seemann]

Also agree on the square of baltic birch. Cutting the grove before you miter the ends should make it easier and safer, and you can use a regular tenoning jig then.

[Bryan Knitter]

Thanks for the input everyone! I think I'm going to try the square spline using 1/4" baltic birch. I haven't even though to cut the groove before mitering the ends though, that's a great idea and should be much safer. Thank you for that suggestion Andrew!

[Nick Decker]

Sounds like you've got your answer, Bryan. Just curious, how do you clamps these pieces together when gluing? Very elegant design.

[Bryan Knitter]

Sounds like you've got your answer, Bryan. Just curious, how do you clamps these pieces together when gluing? Very elegant design.

Thank you Nick, I really appreciate it!

To clamp these, I built a simple jig and clamp 1 half at a time. Then, when I clamp both halves together, I use the wedges that got cut off when I cut the miters in each corner and clamp it like an X.


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[Nick Decker]

Nice. Thanks for the explanation.

[Edwin Santos]

Thank you Nick, I really appreciate it!

To clamp these, I built a simple jig and clamp 1 half at a time. Then, when I clamp both halves together, I use the wedges that got cut off when I cut the miters in each corner and clamp it like an X.


382376

Nice clamping setup Bryan, well thought out!

[mreza Salav]

A good dowel jig (like Jessem) is VERY accurate, in fact it is more accurate than Domino. I have Domino and both jigs from Jessem and whenever I want super accuracy I use the dowel jig.

[Al Launier]

That truly is a beautiful cross - love the joinery - love the selection of wood!

A square hardwood spline immediately came to mind. Looks like a consensus. Should be easy to set up on a TS & slot it before the mitering, give you a more solid joint, and still be a blind joint.

Like mreza I also have a jessem dowel jig and can testify how accurate it is. I believe this would also make a strong joint using quality hardwood dowels.

[William Young]

I think the above described spline sounds like a good idea. However, I think there are a couple of alternative methods that might be worth considering.
The 1st method is a modified half lap and leaves either the vertical or the crossing piece whole so that you will have to glue-up only 3 pieces rather than 4. Start by cutting the 1st half of the lap in a crossing pattern rather than straight across as you normally would with a half lap joint. You will then rout away the two side triangles. Now cut the other two pieces with the end triangles as you usually do, but then rout away the back half. These then are glued to the 1st piece half lap fashion. You will be left with a similar look, but with a much easier glue-up and more strength (compared to your original method).
The second method is also a modified half lap. Cut all your pieces as you normally have done. Now cut or rout away the back half of all triangles. Cut a "spline" as mentioned above, but make it 1/2 the thickness of you work pieces. Glue it into the routed square on the back side of the points during assembly. Since it is on the back side it will not be seen, but it will provide suitable reinforcement to the joint. This method might be the easiest and simplest of all the methods discussed.
For those crosses that you have already made: If you want to add some strength for insurance, you could rout out a void on the back of all the triangles and glue in a square insert of about 1/2 the work piece thickness. This would add considerable strength without being visible.

[Edwin Santos]

Bryan,
I have a Jessem dowel jig and agree it would do a good job. Do you have a biscuit joiner? If so, I think it would be a fine solution also. If you go that route, do some online searching for a FWW article that shows how to build a small table for securing your biscuit joiner and turning it into a stationary tool. If you can't find it, let me know and I can send it to you. It increases the accuracy of the tool and would work very well for this with an angled fence secured to the table. This setup would allow you to produce these items in volume very efficiently.

Another option, you could make a simple dowel jig custom to your project using Lee Valley drilling bushings which come in 1/8" 1/4" and 3/8" sizes. The insert goes in a 5/8" hole, and for a considerable amount less, your jig could be just as accurate as the Jessem, just not as versatile because it is built specific to this one project. I had a job that required end joining 3" round poles and my joinery method was to make a special doweling jig in this way using multiple 3/8" dowels.

The simplest solution perhaps - don't add any joint reinforcement.
I don't cringe nearly as much as some at the idea of an endgrain joint. For something like this, maybe consider "painting" the joints with a glue size, let it soak in, and then apply your real glue and clamp away. You have a good clamping set up and I think the joint might be stronger than you think just using a high quality glue like TB I, II or III.
In fact, as long as you don't feel it's sacrilegious to do so, make one up as I'm describing, and drop it, throw it, subject it to some reasonable abuse to see how durable it might be, and you may be pleasantly surprised.
IMO the main reason endgrain joints are weaker is because of the manner in which the grain soaks up the glue and then the joint is essentially glue starved. The old timers used an application of glue size or two in order to deal with this.
Hope these ideas help,

Edwin

[Jim Becker]

You could also get fancy and create somewhat of a "broken bridle joint" so that you have better glue surfaces for the side pieces, rather than all end-grain and a continuous piece for the vertical member. That, combined with domino/tenon/splines and screws from the back side would provide a very strong joint. Yes, you'll need to do a little hand work to square up the recesses in the vertical component after hogging it out with a router in several depth passes, but the end result would look identical to what you picture and likely be a lot stronger. You'd be working with three pieces of wood rather than four in this scenario.

[Martin Wasner]

I'd clamp it all together, wait for the glue to mostly dry, and zip pocket screws into each of the angles. That's assuming it wouldn't cut the pocket all the way to the edge where it would be exposed.

[Scott T Smith]

A very simple approach would be to use a tongue and groove on the ends of the boards. Opposing boards to have the same edge (T or G).

This provides side grain for a stronger glue up, and would be very fast to machine.

The drawback is that the T&G joint would be visible on the edges of the cross where the pieces joined.

[Bill Adamsen]

You might try the Hoffmann MU2P(3P) dovetail machine. It is optimized for reflected miters like your example. Might eliminate the need for the clamp (the dovetails are self-compressing).

[Chris Fournier]

Quick and effective as well as hidden - your biscuit suggestion! No need to overthink this one at all.

[Bill Dufour]

What method did the original use? I thought half lap and then bound with rope? Seems like wire wound over the joint would be more authentic.
Please note I like your design. I am just wondering about how the originals were made. Where they a matching set.? Certainly some versions today show an extra ankle rest. Not sure about the double top cross bar type and why two bars there.
Bill D.

[Jerry Olexa]

Very nice work!!! love the miter joint look... some combination of biscuits or splines or a variation of a M/T joint should help..

[Bill Dufour]

Jesus was a carpenter did he have to make his own cross? talk about irony. Wonder how long that job took him.
Bill D.